In a wireless communication system, by concentrating transmitting and receiving power at a narrow space, a research for applying beamforming technology that increases transmitting and receiving efficiency of an antenna is actively performed. For example, discussion for applying beamforming technology to a medical ultrasonic wave system can be performed.
In a wireless medical ultrasonic wave system that supports beamforming technology of an analog method, in each of a probe device and a system device, an array antenna including a plurality of antenna elements can be provided. In this case, by changing a phase of each antenna element, each of the probe device and the system device can enable energy of a radio wave to physically concentrate in a constant direction, and as the number of antenna elements increases, each of the probe device and the system device can minutely adjust a direction of a beam through beam training.
In order to minutely adjust a beam in an entire direction, each of a probe device and a system device should include as many antenna elements as possible. However, as an antenna element substantially increases, it is very difficult to technically implement this, and a cost increases, and thus it is difficult to have many antenna elements that can minutely adjust a beam in an entire direction. Therefore, in the probe device, because it is difficult to transmit and receive a signal in an entire direction, when the probe device dynamically changes a direction thereof by a user, it has a high failure possibility to transmit and receive a signal to and from the system device.